Measurement of preformed tubes are taken to enable reproduction of such tube configurations. Hopf U.S. Pat. No. 4,122,607, issued Oct. 31, 1978, discloses an instrument for taking such measurements. The tube is fixed onto the instrument table and is measured by engaging a metered mechanical apparatus at points along the straight portions of the tube to define the centerlines of the straight portions. Using this data, the tube configuration may be computed.
When a tube is so long as to extend beyond the boundaries of the instrument, the tube is measured in sections. The tube is shifted so that at least two measured straight sections remain within the instrument boundaries. Those two straight sections are relocated with the instrument and then the remaining straight sections of the tube within the instrument boundaries are also located. These later measured sections can in this way be spatially correlated to the first measured sections of the tube.
A problem has arisen when the tube has a straight section which is so long that it is impossible to spatially locate straight sections defining successive bends within the boundaries of the instrument. I have developed both a method and an apparatus for creating false bends within the long straight section so as to overcome this problem.